The soundness and efficiency of banks is one of the important subjects that neglecting it can have adverse consequences for every country's economy. For economies depending on the money market, such as the Iran economy, this subject is more critical. Therefore, in this study, using panel data related to 16 Iranian banks for the annual period of 2010-2017, the economic efficiency was determined using a translog cost function and stochastic frontier analysis method then, by estimating the model of panel vector autoregression model and Granger causality test, the causal relationships between efficiency and information asymmetry in terms of adverse selection ( the ratio of loans to assets and the ratio of loans to deposits) and moral hazard ( the ratio of non-performing loans), were investigated, both of which are caused due to the information asymmetry. The estimations confirm the unilateral causal relationship of adverse selection and moral hazard with banking system efficiency. And, on the contrary, they claim that low efficiency of the banking system increases the adverse selection and moral hazard is not confirmed. Besides, the results of other estimates based on the panel model with random effects indicate a negative and significant impact of moral hazard and adverse selection on efficiency.